Gear



l March 27, 1945. H. L. BENTON 2,372,625

l f GEAR l Filed Nov. l1, 1942 I 2 Sheets-Sheet l `March 27, 1945. H L BENTON l A 2,372,625

GEAR

Filed Nov. ll, 1942 2 Sheets-,Sheet 2 Patented Mar. Z7, 1945 "GEAR .l HarryL Denton, Chicago, Ill.,.as'signor to Wenzel Projector'Company, Chicago, Ill., a ycorporation H'oi' Illinois Application November 11, 1942, Serial No.- 465,276

` g; 3 claims. (0114-411) j This invention `relates primarily yto'motion picture `projector lapparatus and;r secndarly,.:toa newand improved gear. 4Whichmay be used in conjunction with .motion j picture; projectors as Well as elsewhere anw-otherwise.

AIn the art. of motion picture.projectorsfof.y the commercial type, a substantial dii'llculty hasheen experiencedA for many vyearsfin. the.A form fof. a vibratory or .oscillatory-movement imparted to certain. parts of the operating. :mechanisms and.

particularly to lthose parts .ottheoperating mechanisms whichy are associated with theintermittent movement, and its ,L fly wheel, `and thejshutter vwhich alsofunctionsmore or lessas.. a y wheel.

It hasbeen found in theuseof commercial motion picturel projectors and particularly those of the so-called 35 mm. type, '.that the intermittent movementl fly Wheel andthe shutteritend to over run each other. suddenshock to certain parts of the operating mechanisms of the projectorwand consequent tendency to strip certain of thef'gearsinv the operating mechanismof theprojector. Moreover, this difliculty also tends-to set up anos-- cillatory movement in certain parts ofthe operating mechanisms of the projector which results in noisy operation thereof. Thisisbelieved=to bedue,V in part;r atleast, fto'iilm pull or drag andthe `tendencyofj lilm pull or drag to retard the speed of the intermittent movement flywheel andA the resulting oscillatory movement `of `the intermittent movementfriy` 'wheel may readily be-seen by examining operating mechanisms "of al motion picture projector:l apparatus with A a combination stroboscope-taehometer such, forexample, asv that which -isV known. by y"the1 trade` name Strobotac (GeneralI RadioCOmpany).

Various attempts ihave been made heretofore toV overcome the foregoing. and `related difficul-` ThisA tendsv toA cause .A furthery object of the invention :is .to aiordn afnew and improvedzmotion picture projector embodying a -novel cand-..eicient intermediate gear .assembly which, in` use,A compensates-for the tendency of the intermittent. movement flywheel and the shutter to over run each other and cause noisyoperation of .the projector. and tendency toastrip .certain of the gears .in the operating mechansmshofvthe, projector;- and other incidental, or relateddiicultes.

A Another objectof vtheinvention is to afford, in one formor embodiment thereof, a novel shutter hub construction which, in use, compensates forthe tendency` of the intermittent movement ily Wheel and shutter to over run each other and cause noisy operation of the projectorand a tendency to 4`strip' the' teethV o-nI certain of the gears in 'the' operating mechanism of the projector, and other incidental` or related difficulties arising from theaforesaid tendency of4 the intermittent movement fly wheel and vshutter to overrun each other and setup oscillatory movementinthose'parts of the operating mechanisms of the projector which are associated therewith.

Another object of the invention'is to afford a novel intermediate gear assembly fora motion picture projector andvvhich embodies parts hav-` ingv a'limited' circumferential movement relative to each other-but which are so constructed and arranged thattheyfarenotfcapable of either axial or radial-movement with-.respect to veach other, therebyeompensating 4for Va tendency'of the intermittent movementrly wheel and shutter to over :run each other while, at the same time,v avoiding bothi axial` and radial movement ofcertain ofthe componentV parts of' the new intermediatev gearV assembly 'andA the resultant noisy operationv and tendency to stripping of gears 'which' has been incidental tothe use' of other intermediate gear constructions" intended to scription and claims andrwillbe. understood by reference to the accompanying drawings which,

Fig. l is a view, partly in side elevation, and" partly in section, showing parts of a commercial motion picture projector having the present invention embodied therein, one side wall of the projector housing being removed so as to show the arrangement `of the parts therein and the shutter housing being shown in section so as to show the shutter arranged therein;

Fig. 2 is an enlarged central vertical sectional View showing a preferred form of the new intermediate gear assembly and the arrangement thereof in the projector which is illustrated in Fig. 1;

Fig. 3 is a view on line 3-3 in Fig. 2 partly in section and partly in side elevation, illustrating the new intermediate gear assembly;

Fig. 4 is a side elevational view of a modified form of the present invention and illustrating the invention as embodied in a shutter hub construction;

Fig. 5 is a transverse sectional View on line 5 5 in Fig. 4; and

Fig. 6 is a View on line 6-6 in Fig. 5 partly in section and partly in elevation and illustrating the construction of the form of the invention which is illustrated in Figs. 4 and 5.

A preferred and typical embodiment of the present invention is illustrated in Figs. 1 to 3, inclusive, wherein the present invention is shown as being embodied in a commercial motion picture projector of the rear shutter type, and those parts of such a projector are shown and will be described herein as are necessary to illustrate a typical and preferred environment in which the present invention is employed.

The rear shutter type projector which is partially illustrated in Fig. l comprises a housing I9 including a, vertical front wall II, a vertical rear wall I2, a top wall I3, a bottom wall I4 and a vertically extending central partition I5. Mounted shaft 60 which extends parallel to but below the rear shutter-operating shaft 26. The stub shaft 60 carries a gear 6I which meshes with a gear 62 on the shutter-operating shaft 20.

The intermittent movement of the rear shutter type projector, which is illustrated in Fig. l, is generally indicated at 21 and includes a fly wheel 28 carried by the center shaft 34 of the intermittent movement. Motion of the intermittent movement 21 and its fly wheel 28 are transmitted to the lm advancing mechanism (not shown), in a' manner which is Well understood in the art and hence need not be described in detail herein.

As shown in Figs. 1 to 3,` inclusive, the new and socalled intermediate gear assembly 26 is associated Witha horizontally extending supporting shaft 29 and comprises a body portion or part 3D which is preferably metallic and which is shown as being formed as an integral flange upon the shaft 29. This part 30 of the new intermediate gear assembly 26, as shown in Fig. 3, has-beveled gear teeth 36a formed thereon, on its peripheral edge, and these teeth 30a mesh with one of the tworows of beveled teeth upon the double beveled gear 24.

The new intermediate gear assembly 26 also includes a centrally arranged and main gear element 3I which isprei'erably formed of resinous or plastic material and this main gear element 3| of the intermediate gear assembly 26 is provided on its peripheral edge with a row of spuror spiral teeth 25 which mesh with a row of corresponding teeth 32 on a gear 33 which is carried by the center shaft 34 of the intermittent movement 21.

The body of the main gear element 3| of the new intermediate gear assembly 26 has an annular recess 35 formed in one side wall thereof and disposed in this recess 35 is an annular and preferably metallic face plate 36. The plate 3G is provided with preferably at least three screw threaded openings 31 (Fig. 2) each of which is adapted to receive the threaded end portion i' of a bolt 38 which, and the bolts 33 and the screw threaded openings 31 therefor, are preferin the housing IIJ, and secured to the central vertical' partition I5, las at the points I6, I1l and I8, is a rear shutter shaft supporting bracket I9 which has a plurality of bearing portions in which a horizontally extending rear shutter-operating shaft 2D is journaled, the rear shutter-operating shaft 20 having a portion which extends rearwardly of the rear wall I2 of the projector housing and said extension carries the rear shutter 2'I which is arranged in the rear shutter housing 22. As shown in Figs. 1 and 2, the rear shutteroperating shaft 2 is driven from a vertically extending drive shaft 23 which carries a double bevel gear 24. The upper-end portion of the vertically extending drive shaft 23 is journaled in a bearing opening which is provided in the rear shutter shaft supporting bracket I9 and the lower end portion of the vertically extending shaft 23 is jour'naled in a bearing (not shown) but carried by the vertical partition I5. The upper row of teeth on the double bevel gear 24 meshes with a bevel gear 51 which is carried by a stubrelative to the plate 36 of the intermediate gear assembly 26, as shown in Figs. 1 to 3, inclusive.

As shown in Fig. 2,- the new intermediate gear assembly 26 includes a plurality of metallic ferrules or rings 39, each of which is arranged in an opening 61 formed in the body of the main gear element 3|, around the bolt 38 therein, and between the two spaced cooperating parts 30 and 36 of the intermediate gear assembly 26. Surrounding each of the ferrules or rings 39, in each of the openings 61, is a compressible resilient cushioning element, inthe Yform of a ring or ferrule 49, which is preferably made of resilient material such, for example, as natural or synthetic rubber or like material.

A small helical gear 4I is carried by an enlarged portion 63 of the shaft 29 at one side of the plate 36 which is embodied in the new intermediate gear assembly 26 and this gear 4I is keyed to the enlarged portion 63 of the shaft 29, as at 54 (Fig. 2). A screw or bolt 42 projects through an opening formed in the small helical gear 4I and into a screw threaded opening which is tapped in the enlarged portion 64 of the shaft 29, as shown in Fig. 2

As shown in Fig. 2, a metallic bearing and.

spacing ring 66 is arranged around the lenlarged portion 63 of the shaftv 29 within a correspondmg .opening in .une part 3| for .me intermediate gear assembly .26. As is alsoshown in Fig. 2, a

retaining washer `|54 carried `by the clamping washer 64, for a reason which will be explained presently.

The ring 66, as shown in Fig. 2, not only spaces the `cooperating parts 30 and 36 .of the intermediate gear assembly 26 but ralso provides a bearing for the central and main gear element 3| thereof, and when the .bolt 42 is tightened to secure the parts of the intermediate gear assembly 26 in position of use, as in Fig.. .2, the spacing ring 66 prevents pressure .exerted upon the plate '36 from binding the two spaced cooperating parts 3| and 30 of the intermediate `gear assembly .2'6 together which would prevent a desired 'limited relative movement between these parts, .as will be explained more fully hereinafter..

As shown in Fig. 2 the limited clearance Bil allowed between the outer end of the enlarged portion 63 o'f the shaft v29 and the outer surf-ace of the small 'helical gear 4| enables the retaining washer 64 to be Aforced by tightening oi the bolt 42 slightly inwardly (left to right, Fig. 2)

so.as to force the retaining `washer into binding t engagement with the small helical gear 4| and thus assure that these parts of the intermediate gear assembly 26 lwill be securely held together.

As shown yin Fig. l, the small helical gear 4i meshes with a gear 55 which, in turn, meshes with a gear 56, and these gears "55 and 5E are a part of a gear train which is embodied in the operati-ng mechanism of the projector.

In the use oi the form of the invention which ifs shown in Figs. l to 3, inclusive, of the drawings, the rear shutter operating shaft 2B, and the rear shutter 2| which `is carried thereby, and the intermittent movement 2l and its fly wheel 28, are all operated or driven in a Imanner which is well understood in the art and hence need not be .described in detail herein.

In the .operation ci a commercial motion pic ture projector yembodying the present invention, and such as is illustrated in Figs. 1 to 3, inclusive, of the drawings, any tendency of the shut ter 2l and intermittent movement ily wheel `2li toover run each other and set up an oscillatory or yibratory motion the mechanisms asscciated therewith, and consequent noisy loperation of the projector, as well vas a tendency to cause stripping of the teeth of the gears embodied in the intermediate gear assembly and other gears associated therewith, is eliminated or compensated for by the novel construction and arrangement .of the new intermediate gear assembly. This is due to the .novel construction of the intermediate gear assembly 216 including thecushinning devices 39-40 which are so constructed and arranged that .any tendency of the intern mittent movement fly wheel 2B, acting through the gear 32-33., and the teeth 25 of the intermediate gear assembly 26 to over run the shut ter 2|, will be absorbed or cushioned by :and compensated for by the intermediate gear assembly .26 and the cushioning devices 39-48 which are embodied therein and, similarly, any tendency of the shutter 2| to over run the intermittent movement ily` wheel 21 Awillliicewise..be absorbed or cushioned by and compensated for by the new intermediate lgear assembly 26 and the cushioningv devices 39-48 which are embodied therein. *i

.It will :be noted, in this connection, and by reference to Figs. 11 to `3, inclusive, oi the drawings, that the ange .3B of the intermediate gear assembly shaft 29is bolted to the plate 36 thereof .so that the flange Si! and the plate`36 vneces'- sarily `move together, as a unit, and cooperate together to form .a part oi Athe intermediate :gear assembly 26, and which unit 3|l-36 is capable oi a limited circumferential .movement only relative to the other principal part of the intermediete A,gear assembly 26, nam-ely, the main or central gear element 3l| thereof.

As pointed out hereinbefore, the new intermediate gear assembly 26 is so constructed and arranged that `the parts eitil-w36 .and 31| thereof are conned to a circumferential movement relative to each othenso that any oscillatory motion, which :may beset up in the projector mechanism, is absorbed or compensated for by the new intermediate `gear assembly 26 and its cushioning'da vices 39-40 and hence :does not cause, nor tend to cause, either radial-or .axial movement of the intermediate gear .assembly`26 upon or relative to the .intermediate gear. assembly shaft 29, as has occurred in prior art intermediate gear assemblies which have been .employed heretofore in an endeavor to compensate for oscillatory movement set up in the operating mechanism of the pro- 4jector by the oyer running of the shutter 2| and the intermittent lmovement :fly wheel 28 caused by drag or otherwise. y i

for example, .assuming that the shutter 2| .should over the intermittent movement ily wheel 2'8, by reason of film drag or for .any other reason, one effec-t .of this in the prior art projectors would be to act through the shutter operating :shaft 2|), gears 62 .and 6| stub .shaft 60, bevel .gear 51, the double bevel gear 24, .and the vertically extending :drive shaft 23, to cause noisy operation and possible stripping of the intermeshing gear teeth on the double bevel gear 24 and the intermediate Agear assembly `26. However, in

7 the practice of the present invention, such oven running of the shutter 2| is compensated for by reason of the fact that such over ruiming of the shutter 2| merely acts, through the shutter-operating Ishaft 20, gears 62 and 6|, stub shaft 60, bevel gear 51, double bevel gear y2t and the lower row of teeth there-on, the row of bevel gear teeth 30a on the flange or portion 3|) of the intermediate gear assembly 26, the plate 36 and bolts 38 and small metallic ferrules or rings 39, to impart a limited circumferentialu movement to the parts 311-436-38-39 of the intermediate gear assembly 26, relative to the main gear element 3| thereof. This limited circumferential movement'is made possible by reason of the cushioning eiect of the small resilient or rubber rings or ierrules 40 and not only compensates for such possible over running of theshutter 2| but effectively prevents any stripping of the intermeshing teeth on the double bevel gear 24 and the teeth 30a on the intermediate gear assembly 26 but also has the additional advantage of preventing noisy operation of the projector which would otherwise result and as occurs in the use of prior art projectors of an otherwise similar character.

Similarly, for example, if the intermittent fly wheel 28 should over run the shutter 2|, this is compensated for by reason of the fact that such motion will merely act, through the gear 32-33 and the teeth 2 5 of the intermediate vgear assembly 26 to `impart alimited circumferential movement -gear 'assembly 26, relative to the spaced and cooperating parts 30 and 36 thereof. Such limited circumferential movement of the main gear element 3| of the intermediate gear assembly 26, relative to the parts 30 and 36 thereof, merely compresses the small resilient or rubber ferrules or rings 40 around and relative to the hard and incompressible small metal ferrules or rings 39, thereby compensating for any over running of the intermittent movement fly wheel 28 relative to. the shutter 2| and not only preventing possible stripping of the gears but also preventing noisy operation of the projector which would otherwise result from such over running of the intermittent y wheel 28 relative to the shutter 2|.

While the form of the invention which is illustrated in Figs. 1 to 3, inclusive, is a preferred construction and arrangement of the invention, as

embodied in an intermediate gear for a motion l picture projector, a modification of the invention is illustrated in Figs. 4, and 6 of the drawings and in this form of the invention the same is associated with the shutter 43 and its hub structure which is generally indicated at 44.

As shown in Figs. 4, 5 and 6, the hub structure 44 of the shutter 43 includes a body 45 having a split'sleeve or collar portion 46 which is adapted to be mounted upon the shutter-operating shaft of a motion picture projector.

As may be seen by reference to Fig. 5, the body 45 of the hub structure 44 has an annular flange 41 formed thereon and integrally therewith and a centrally apertured annular plate or disc 48, of approximately the same diameter as the flange 41, is mounted upon the hub portion 45 in spaced relationship with the flange 41. v

The shutter blades 43-43, which are preferably integrally joined by a central web portion 43a, are, as shown in Figs. 4, 5 and 6, attached, by screws or bolts 50, to a centrally apertured annular carrier plate or supporting disc 49 which is arrangedupon the hub body 45 between the annular flange 41 and the disc 48, as best shown in l Fig. 5.

As may also be seen by reference to Figs. 5

. and 6, the disc 49, which carries the integrally connected shutter blades 43, is provided with a plurality of annular openings, as 58, which are preferably at least three in number, and which n are arranged radially around the said disc 49 at intervals of preferably approximately 120. Inserted into each of the openings 58 is a small compressible resilient or rubber ferrule or ring 53 and arranged within each of `these small resilient or compressible rubber ferrules or rings 53 is an incompressible and preferably metallic ferrule or ring 52. Bolts 5| are extended through openings in the ange 41 and one of these bolts 5| extends through each of the small metal ferrules or rings 52 and is inserted into a threaded opening, as 59, provided in the disc 48, thus completing the assembly of the shutter hub structure shown in Figs. 4, 5 and 6.

The operation and use of that form of the invention which is illustrated in Figs. 4, -5 and 6 are substantially similar to the operation and use of that form of the invention which is illustrated in Figs. l, 2 and 3.

Thus, for example, if the shutter 43 should tend to over run the intermittent movement fly wheel, such over running of the shutter 43 will be compensated for by reason of the fact that such over running of the shutter 43 merely tends to act,

2,372,625 to the main gear element 3| of the intermediatethrough the disc 49, to compress the small resilient or rubber rings or ferrules 43 relative to and upon the incompressible small metal ferrules or rings 52. Hence, such overrunning motion of the shutter 43 will not be transmitted through the shutter-operating shaft to the other parts of the operating mechanism of the projector, such as are shown in Fig. l, and hence the tendency to stripping of gears and noisy operation of the projector, and other difficulties, which would otherwise be caused by such over 'running of the shutter 43, are substantially eliminated in the use of that form of that invention which is shown in Figs. 4, 5 and 6.

While the invention has thus been specifically illustrated and described as applied, in two different forms thereof, to a motion picture projector of the rear shutter type, it wil1 be understood that the new gear construcion which is illustrated in Figs. 2 and 3, as well as the structure which is illustrated in Figs. 4, 5 and 6, may be employed in connection with and as a part of other machines and devices and hence the invention, in its broader aspects, is not limited to use in motion picture projectors although it is in such devices that it will undoubtedly find its greatest utility.

It will also be understood, in this connection. that while the invention has been illustrated as being embodied in a motion picture projectoriof the rear shutter type the invention is equally useful with motion-picture projectorsof the front shutter type, and in which, as'will readily be appreciated by persons skilled in the art, the shutter 2| and its housing 22 are associated with an extension of the shutter-operating shaft 20 to or at the front of the projector housing (lefthand side as seen in Fig. l) rather than at the rear or right-hand side, as illustra-ted in Fig. l of the drawings.

It will thus be seen from the foregoing description, considered in conjunction with the accompanying drawings, that the present invention accomplishes its intended objects, and has the desirable advantages and characteristics, including those which have hereinbefore been specically pointed out, as well as others which are inherent in the invention.

While I have illustrated and described selected embodiments o f my invention, it is to be understood that these are capable of variation and modication and I therefore do not wish to be limited to the precise details set forth but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

1. A gear assembly comprising a main gear element including a gear body having an annular row of teeth provided on its peripheral edge and having a cylindrical central opening formed therein affording a cylindrical bearing surface coaxial with said annular row of teeth, said body member also having opposite side faces disposed parallel to each other and alfording fiat bearing surfaces perpendicular to the axis of said cylindrical bearing surface, said gear assembly including means defining an external cylindrical bearing surface disposed within and in bearing engagement with said internal bearing surface of said main gear element, and said gear assembly also including a pair of spaced cooperating parts arranged one on each side of the said main gear element of said gear assembly and having at surfaces opposed respectively to said fiat bearing surfaces of said body member to maintain said main gear element against tilting with respect to said axis of said cylindrical bearing member, means interconnecting the said pair of spaced cooperating parts of said gear assembly together for limited movement as a unit relative to the said main gear element of the said gear assembly, and compressible cushioning means arranged between the said spaced cooperating parts of said gear assembly, and within the body of the said main gear element, and compressible under the action of said interconnecting means for cushioning limited rotative movement of the said pair of spaced cooperating parts of the said gear assembly relative to the saidmain gear element thereof, one of said two spaced cooperating parts including a peripheral edge portion having a number of beveled gear teeth formed thereon, the said body of the said main gear element having a substantially annular recess formed in one side thereof, and the other of the said two cooperating parts of the saidgear assembly being a substantially annular plate or disc mounted in the said substantiallyannular recess formed in the said body of the said main gear element.

2. A gear assembly as deiined in claim l in which one of the said two spaced cooperating parts thereof includes a peripheral edge portion having a row of beveled gear teeth formed thereon, and in which the said body of the said main gear element has a substantially annular recess formed in one side thereof and in which the other of the said two cooperating parts of the said gear is a substantially annular plate or disc mounted in the said substantially annular recess in the said body of the said main gear element, and in which the said one of said two spaced cooperating gear parts which has the said row of beveled gear teeth formed on its peripheral edge is arranged in contact with and at the side of the said body of the said main gear element which is opposite the said side thereof at which the said substantially annular plate or disc is disposed in the said recess formed in the said body of the said main gear element.

3. A gear assembly as donned in claim 1 in which one of the said two spaced cooperating parts thereof includes a peripheral edge portion having a row of beveled gearteeth formed thereon, and in which the said one of the said two spaced cooperating parts of said gear assembly is formed integrally with, and as a substantially annular flange upon, a shaft for supporting the said gear assembly.

HARRY L. DENTON. 

